1. Field of the Invention
The present invention relates to a data storage device. Further, the present invention relates to a method of erasing data stored in a data storage device.
2. Description of the Related Art
When selling or disposing of a computer, the owner of the computer usually formats the hard disk of the computer in order to prevent data stored in the hard disk from being seen by others.
However, a hard disk format program such as one included in Windows™ does not completely erase data stored in a hard disk.
To be more specific, the hard disk format program only initializes the management area in which dates of creating data, data sizes, addresses indicating the storage locations of data, etc. are stored. In other words, the hard disk format program does not initialize the data area in which data are stored.
Therefore, even after the hard disk is formatted by the hard disk format program, data are kept in the data area.
The data kept in the hard disk after being formatted can be read out by, for example, software for restoring data which has been erased by mistake.
Accordingly, in order to securely prevent data stored in the hard disk from being seen by others, data in the data area needs to be erased.
Hence, there have been attempts to completely erase data stored in the hard disk by writing predetermined data both the administration area and the data area.
In this case, the main body of the computer (specifically, the CPU (Central Processing Unit)) designates data to be written upon and locations of data writing. The hard disk writes the data designated by the host computer on the designated locations.
When writing of the data on the designated locations is completed, the host computer designates data to be written upon next and next locations of data writing. The hard disk writes the data designated by the host computer on the designated locations.
By repeating this operation, the data stored in the hard disk are completely erased.
However, according to this method, communications are repeated many times between the host computer and the hard disk from the start of data erasing until the end. Therefore, if the hard disk has large capacity, there arises a problem that it takes a long time to erase all the data stored.